This invention relates to hand-operated parking brake actuators. More particularly, the invention relates to a pull-to-release brake actuator, wherein the actuating handle is returnable to a stored position with the brake applied.
Hand-operated parking brake actuators for automotive applications are of two principal types. The first includes a non-retractable hand-operated lever which is pulled from a released position to an engaged position. This type of actuator typically includes a stationary ratchet sector gear and a pawl which moves with the lever arm and engages the sector gear to hold the lever arm in an engaged position. A brake cable attached to the lever arm is appropriately held in tension. To release this type of actuator, typically a disengagement member operated by the operator physically pushes or pulls the pawl from engagement with the sector gear teeth.
Another type of non-retractable actuator is disclosed in U.S. Pat. No. 3,580,104. That actuator incorporates a stationary ratchet sector and pawl mounted on a hand-operated lever. The pawl in this device is adapted to hold the lever and brake cable in the applied position and to automatically release from engagement with the sector upon reapplication of a force on the lever in the direction of engagement to allow the lever to return to the released position. This type of release mechanism is known as a pull-to-release since activation of an auxiliary release member is not required, but rather, the operator only needs to pull the lever slightly past the engaged position to release the pawl from engagement with the sector. It should be noted, however, that in both type of actuators just described, the actuating lever is non-retractable and remains in the engaged position with the brake applied. PG,3
The second principal type of hand-operated brake actuator is known as the retractable-type. In this type of actuator, the actuating lever arm is returnable to the stored or released position with the brake remaining applied. These actuators typically include a pivoting ratchet sector operated by the lever arm which is engaged by a stationary pawl. The brake cable is affixed to the pivoting sector and is held in the engaged position by the pawl. Since the lever arm is separate from the sector it is returnable to the released position with the sector and cable held in engaged position by the pawl.
Release of this type of actuator is also achieved by operating an auxiliary disengagement member which engages and physically moves the pawl out of engagement from the sector. Heretofore, the pull-to-release feature such as that applied to non-retractable actuators, has not been applied to the retractable type brake actuator.